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12
This graph shows that the highest efficiency in coding compresses the image in YUV color model 4: 4: 4. This is due to the fact that this model provides a better grip when using the DCP by using different color difference components. As is known, the human eye is more sensitive to color brightness than to its color components. Model 4: 4: 4 is used as a time when imaging, are saturated with a rather small details and sharp transitions in color difference components.
The effectiveness of image reconstruction was estimated standard deviation ofMSE (mean square error) and PSNR (Peak Signal to Noise Ratio), which are calculated according to the formulas [5]:
snr = 20 ■ log1(
255
4msE'
(2)
Torgk
mse =
-Re s,
w-h
(1)
According to the calculations of all the studies, the compressed image reconstruction error with the same error recovery algorithms applied JPEG, i. e. the proposed conversion method does not affect image quality.
Conclusion. The proposed method allows to obtain high homogeneity and a correlation between pixels, thereby increasing the compression ratio in some images, however, additional metadata input for further recovery, increases the volume of the final output file. Compression using standard metodannyh archives increases the efficiency of the method. Therefore, the use of archiving algorithms after the proposed brightness changes will involve an increase in the compression ratio.
References:
1. Jian Song, Zhixing Yang, JunWang. Digital Terrestrial Television Broadcasting: Technology and System. IEEE Press. Canada. - 2015. -456.
2. Под редакцией Соатова Х. С., Гаврилов И. А., Рахимов Т.Г, Пузий А. Н., Носиров Х. Х., Кадиров Ш. М. Цифровое телевидение: Top Image Media press, - Tashkent, - 2016.
3. Носиров Х. Х., Уменьшение размеров изображений для увеличения коэффициента сжатия, и его влияние на качество восстановления в кодеке Дирак//Ежемесячный научный журнал Евразийский союз ученых, - № 9 (30)/ - 2016, - часть 2, -Москва, - 2016.
4. Артюшенко В. М., Шелухин О. И., Афонин М. Ю. Цифровое сжатие видеоинформации и звука: И.: - Москва. - 2003. - С. 430.
5. Salomon David. Data Compression: The Complete Reference (4 ed.). Springer. - 2007. - P. 281. - ISBN 978-1846286025. - Retrieved 26 July - 2012.
DOI: http://dx.doi.org/10.20534/ESR-17-1.2-192-194
Bakiev Masharif Ruzmetovich, Professor in the department «Hydrotechnical construction and engineering structures», Tashkent institute of irrigation and melioration (TIIM), Uzbekistan
E-mail: [email protected] Kahhorov Uktam Abdurahimovich, Senior teacher at the department «Hydrotechnical construction and engineering structures» Tashkent institute of irrigation and melioration (TIIM), Uzbekistan.
E-mail: [email protected]
Estimation of velocity fields beyond transverse dams at the region of flow potential energy restoration
Abstract: Using main clauses of the theory of turbulent jets, the authors introduce relationships to calculate velocity fields and length of restoration region of the potential energy of flow constrained by bilateral floodplain dams.
Keywords: floodplain, channel, momentum conservation equation, discharge conservation equation, traction forces, velocities in channel, velocities at floodplain, length of potential energy restoration.
Rapid population growth in Uzbekistan, reaching 34,7 mln in 2025, will put on agenda the task of effective use of available land resources, including floodplain lands, and also the task guaranteed water supply into irrigation canals. These tasks can be solved by construction of transverse dams on river floodplains, since erecting transvers dams from local material is much cheaper than bank paving longitudinally.
On the other hand, the regional ecology of rivers in the Aral sea basin is worsening. Construction of regulation structures improves the local ecology: prevents riverside lands from water erosion, allows for regulation of floodplain land use, facilitates the drop of river wa-
ter level for the purpose of improving reclamation state of riverside lands, and, in addition, nowadays the question arose about bringing water to Aral by regulating Amudarya river floodplain at its delta.
Meanwhile, the movement of flood itself in channels with immersed floodplain forms under influence of channel and floodplain complex morphology and roughness, kinematic and dynamic interaction of channel and floodplain flows. At present, there is no methodic for designing bilateral transverse dams at floodplains, therefore conducting high-cost research is needed to justify such projects.
Estimation of velocity fields beyond transverse dams at the region of flow potential energy restoration
It is known that flow spreading is mainly influenced by structural characteristics of dams: degree of contraction, symmetrical or asymmetrical contraction, installation angle, and morphological characteristics of floodplain: depth, unilateral or bilateral, same roughness, varying roughness, hydraulic regime, and etc. [1; 2; 3; 4; 5].
Area III is characterized by that flow potential energy is restored i>0. Flow velocity along riverbank can't be ignored, besides it is necessary to know the magnitude of these velocities in order not to allow for erosion of this bank.
The pattern of width change in the first zone of mixing
B = bK + 0,1x ; b' = b'k + 0,1Z ; B K, = B KJe0 ; e ' = e'/e0 ; (1) In the second zone it stays the same as before
e" = e" + 0,27x ; 7' = 7„ + 0,27Z ; Z = x/e0 (2) Since we are analyzing symmetrical flow contraction, flow failure is not observed for the reason of floodplain symmetry and the
length of the analyzed region does not exceed 10^15% of the length ofvortex zone beyond the contracted section line L"s. Therefore we can neglect traction force influence at short distance. Water depth increment is taken as follows h = h + Ix or h = h + Ix
p pc nn pnc
where dh/dx = I = hp6 - hpjLIII = const. hnn = hnnc + Ix (3) In order to solve the task we used flow momentum conservation and discharge conservation equations. Besides, we have boundary conditions for section line K2 — K2: restoration ofthe original flow condition occurs at the end of flow restoration region: hp = hp6;
Up = Uo; U = U ,; U = U ,.
p po ' nn nno ' nn nno
We generate the equations for section lines K — K and
X, — X :
/1 "n ~n '-p -p ~V n
ph \U2dy + ph U2 e' + ph \U2dy + ph„ f Udy + phU2 e + phc fUdy + phc f Udy + ph U2 e" +
r nnc J / r nnc nnx1 annx1 r mc J / r pc J / r pc pK1 a r pc J / r pc J / r nnc nnK annK1
0 0 en 0 Bp
y 6 y en en+ep ep ep+en
+pkcJUdy = phmjUdy +phmU2me'm +phmjUdy +php j Udy + phpUpeM + phfjUdy + phf j Udy +phnU2nne';nn + (4)
+phJU2dy + YBp (h], - h2 ) + y ^ (hl - h2 ) + y ^ (hl - h2 )
Discharge conservation equation
y 'n 'n+'p 'p 'p +'n y,,
h \Udy + h U B' + h fUdy + hc f Udy + hUn b + h fUdy + hc f Udy + h U b" + h fUdy =
mc J / mc n^K1 amK1 mc J / pc J / pc pK1 x pc J / pc J / nnc nnK1 annx1 nnc J /
0 0 'n 0 'p ys
yi 'n 'n+'p 'p 'p +'n y,
= h fUdy +h U b ' + h fUdy + h f Udy + hUB + h„ f Udy + h„ f Udy +h U b " + h f Udy
nn J / nn nn xm m J / ^J ' P P x p J / ^J ' nn nn xnn nn J J
By integrating the equations we have:
in the mixing zone at the left floodplain at section line Xx — Xx
( -U)/(Um ) = (1 -n1^ (6)
at section line K — K1 Um = 0
(Um -U)/U„ =(1 -r,») (7)
In the mixing zone at section lines Xj — Xj and K — Kj
(Unn-U )/Unn =(1 n2
In the interaction zone of channel and floodplain flow (U-Un )/{Up-Un ) = (1 -n1'5)1 where n = Y/e' where B = Bn + Bp total width of interaction zone.
By carrying out the integrations in (4) and (5) with the account of 6,7,8,9 we have
(5)
(8) (9)
0,416e' U2 h + h U2 b' - h U2 e'K - h„e'Ul K2 + hU2b + h„eV2„K3 + h U2 b *K. + h U2 b" +
' Ki -rnc une n^Ki ¡mn^ -rnc pKx 1 pc pKx 2 pc pKx x pc pK, 3 nnc pKx 4 nnc nnxl xnnKl
+0,416e" U2 h = h U2 e '(0,416 + 0,268m + 0,316m2) + h U2 e' - h U2b X - he "U2R6 + hU2B + heB'U2K7 + (10)
' K, nnK1 nnc nn nn ^ ' ' H ' H J nn nn xnn nn p 5 p p 6 p p x p p 7
-(h2 - h2 )
nn nnc
+h U2B'K + h U B" + 0,416b"U2 h +^(h2 -h2) + h -h ) +
nn P 8 nn nn XUU ' nn nn 2 p PC 2 nn nnc ' 2
0,55e'U h + h U e' -h Ub'K, -h„U„ e'K,„ + h„U„ b + hB'UKu + h Ub'K„ +
' K nnK nnc nnc nnx imnKi nnc pKl 9 pc pk, 10 pc pKl a pc pk, 11 nnc pKl 12
+h U e" + 0,55h U e" = hUe '(0,55 + 0,45m) + h U e' - h U B'K„ -
nnc nnKl annKl ' nnc nnK, k, nn nn ^ ' ' hj nn nn ann nn p 13
-hUe *K14 + hUe + h e'U K + h U e + h U e" + 0,55e "h U
p p 14 p p a p p 15 nn p 16 nn nn ann ' nn nn
For the given case the symbolic notations are as follows:
Ki = Vi +V2mn„t +vmLt' K2 = w[+w[mmKi +w[; K, +vmm„ +vmL,; K4 = v' + v'5mnn«i + v'm2nn«i; K5 + W2m„, +vrn2m; K6 = +v[mm + v'ml; R7 =vt + vmn + vmln; K8 =v{ + v5mnn + <ml; K9 = v7 + vm™,; Kio = v7+v'mmKi; Kn =w9 + wm,,; Ki2 = v9 + v[omnn„;
K13 =y7 +Vsmn,; m = U ¡U-, m = U /U-, m = U /Up; m = U /Up;
nnKi nnKi I pKx nnKi nnKi I pnn nn I p ' nn nn I p'
= 1,5£4 + 0,143£7 -0,727E5'5 -1,6£2,5 + E; w! = 1,5sP4 - 1,6(ei)2,5 -0,727(BP)5,5 + 0,143(BP?) + Bp; y2 = 1,454E5'5 -0,286E7 -2,5E4 + 1,6E2'5; y/'2= 1,6(Bp)-2,5(Bp)4 + 1,454(ep)5,5 -0,28(6ep)7;
(11)
= 0,143£7 -0,727E5,5 + E4;
= 0,143(eP)7 + (Bp)4 -0,727(Bp)5,5;
0
0
'
¥4 = l,5(eP )4 - l,6(eP )2,5 - 0,727(eP )5,5 + 0,143(eP )7 + Bp ; = 1,5E4 + 0,143E7 -0,727E5,5 - 1,6E2,5 + E;
Vs = 1,6(Bp)2,5 -2,5(Bp)4 + 1,454(Bp)5,5 -0,286(Bp)7; = 1,454E5'5 -0,286E7 -2,5E4 + 1,6E2'5;
We = 0,143(eP)7 + (Bp)4 - 0,727(Bp)5,5; Ve = 0,143E7 -0,727E5,5 + E4;
Vv = E - 0,8E2,5 + 0,25E4; v'l = Bp - 0,8(Bp)2,5 + 0,25(Bp)4;
= 0,8E2,5 -0,25E4; K = 0,8(0,)2,5 - 0,25(Bp)4;
— —2,5 — 4 = Bp - 0,88p + 0,258p ; v'9 = E - 0,8E2,5 + 0,25E4;
Vw — 2,5 — 4 = 0,88p - 0,258p ; vlo = 0,8E2,5 -0,25E4;
E = 1 - Bp ; Bp = Bp / B'
We divide both equations by B0hpc and by carrying out some changes from (10) we get velocity change pattern for flow at channel part
U pKt
B -2 B m2 - -2 B - -2
K--— (hp -1)---—— h—(h„- -1)--—hn„c(hnn -1)
1 2Fr 2Fr 2Fr
pKl n-Kl n„Kl
where
(12)
(M4 B + b'™ )h„nmm- m5b + hpB, + (0,416B" + b"n )hnnmnn
where = (0,416s+ Si^h^m2^ - b (hn,cKl + K2 - K3 -hnacKi) + s.(0,4168% + b" mnKt)hnncm2nnKt; M4 = 0,416 + 0,268mB + 0,316 m2H; M5 = hnK5 + hpK6 - hpK7 - hnnK8;
Bp = Bp/s0; hp = hp/hpc; B, = BJB0; B„ = Bje0; hmc = hmc/hpc; h„ = hnJhpc; hnn = hnn/hpc
= KnJK; = hJh™c; h'nn = Kn/Knc; m™, = U™, / upK, ; m = U ¡Um) Frp = Up /gh ; Fr = U2 /gh ; Fr = U2 /gh ;
nnKJ nnK, f pKx ' pK, pK, j o pc ' nXKt nXKt j o nxc ' nnKt nnKx f o nnc '
As seen from the obtained relationship, velocities in channel parameters, on flow interaction zone parameters. depend on flow kinetics at the initial section line, on relative veloci- From discharge conservation equation we have
ties at floodplains, and on channel and floodplain morphological
UK [(0,55B V + B,n^K,)hmcmra^ - (hn,cK9 + K10 - K11 - hmcKl2)B + b, + (0,55b + b " ^jhmcm^ ] =
= Up[(0,55 + 0,45mB)b' + b]hn*mnR -(hn»Kl3 + hpK14 -hpK15 -hnnK16)B + hpB, + (0,55B " + b",nn)hnnmnn By solving (10) and (11) together we get
Am2m + A2m„R + A = 0 (14)
Aim 2 + A'm2 + A'= 0 (15)
In n 2 nn 3 V /
(13)
A = R2C2ll hn, - (M4 B' - Bm )hm;
A2 = 2fl2hn,(CnhpB, -CUC12b ) + 2R2Cnh„Cuhnnmnn;
A, = (R2C2uhnn -$2Mhnn)ml + (C13hpB„ -Ci3Ci2B')2R2h„nmm + (hpB, -Cl2B')2R2 --M5B*); a; = A2c?3hl - ,}hnn;
A'= (CuhpB, -C13Cj2b )2hnn + 2R2Cnhn*Crhnnmm;
A' = [x&hL - ®2l(Mi ~B' - Bn )hm m+(cnhpBC11C12B * )2 zhm+(hpB, - cnB' )2 m2-^(hpB, - m~b ')
B -2 B m2 - -2 B - -2
M2 = A,--^ (hp -1)--^^^ h„c (hm -1)--n—hnnc (hnn -1);
2 1 2Fr 2Fr 2Fr
pK, rniK, nnxl
(Pj = (0,55bk, + )hnxcmm^ -(hnJ,cK9 + K10 -K11 -hnncKl2)B + 8, + (0,55b"k, + e"^ )hnnMnnKi
C11 = (0,55 + 0,45mH)B + Bm; C12 = hmK13 + hpK14 -hpK15 -hnnK16; C13 = 0,55e" + 7',nn; For the section line K2 — K2 the following equities are true:
U2p6{[L,n(0,1M4 -0,1) + M41'„ + B^jLm^ -M^B' + hp(8, + (0,012!,,,+ 0,416?,! + B.nn^hnntm2^} = U^M, I„,[(0,1M4 - 0,l)hn,im2m6 + 0,0\2hnn6m2nn6 ] + (M4 e + b ' ^jh^m1^ - m5b' + hp6B, + (0,416e + b "„nn^hnnem2^ = ^r
K
And the length of flow restoration region is
U
U
-(m4b\ + bm^hwemlt + m5b -hp6b„ -(0,416B"+ bmk)hnn6m2nn6
-=-=- (16)
(0,1M4 -OMhnxsmlt + OfiUhnnem2^
Hydraulic parameters of flow bilaterally constrained by transverse floodplain dams in the region of its spreading
The obtained relationships include relative velocity along the left bank mn, value that changes from 0 to 1. From the experimental research data we introduce the relationship to describe the character of these changes with the following equation
(17)
U , x 42 m = — = (—)
" и X/
gradual approximation. It is known that these values between the section lines K,-K, and K-K, decrease from U , U , U to
11 2 2 PK\ mK\ nnK\
, V , V" .
po ' HTi ' nn
Knowing this we must give values for mra or mnn and using equation (14,15) determine mnn or mm and further determine Up
with equation (12).
From the obtained values using discharge conservation equation (11) we equate the left and the right parts of the equation. In case if the condition is not satisfied, the calculation is carried out again.
Conclusions:
The analysis of the obtained relationships show, that in this case the task also remains undefined at some degree. There are three unknowns Up, Um, Unn in two equations (12) и (14,15) три
неизвестных величин Up, Um, Uпп, therefore the task is solved by
References:
1. Абрамович Г. Н. Теория турбулентных струй. - М., Физматгиз, - 1960, - 716 с.
2. Барышников Н. Б. Морфология, гидрология и гидравлика пойм. - Л., Гидрометеоиздат, - 1984, - 280 с.
3. Михалев М. А. Гидравлический расчет потоков с водоворотами. Л., Энергия, Ленинград. отд., - 1971, - 184 с.
4. Rajaratnam N., Ahmadi R. Hydraulics of channels with flood-plains. Journal ofhydraulic research. - Voc. 9, - 1981, - No. 1. - P. 43-60.
5. Бакиев М. Р. Совершенствование конструкций, методов расчетного обоснования и проектирование регуляционных сооружений. Автореферат. докт.диссер. - М., - 1992, - 57 с.
DOI: http://dx.doi.org/10.20534/ESR-17-1.2-195-199
Kahhorov Uktam Abdurahimovich, enior teacher at the department «Hydrotechnical construction and engineering structures» Tashkent institute of irrigation and melioration (TIIM), Uzbekistan.
E-mail: [email protected] Bakiev Masharif Ruzmetovich, Professor in the department «Hydrotechnical constructionand engineering structures», Tashkent institute of irrigation and melioration (TIIM), Uzbekistan.
E-mail: [email protected]
Hydraulic parameters of flow bilaterally constrained by transverse floodplain dams in the region of its spreading
Abstract: Using main equations of hydro mechanics, equation of momentum conservation and discharge conservation specifically, the authors of the article introduce design relationships for determining main parameters of flow bilaterally constrained by transverse floodplain dams in the region of its spreading.
The task differs from previous ones by the presence of bilateral floodplain, two zones of interaction between channel and floodplain flows, different roughness at floodplain and in the channel.
Keywords: floodplain, channel, transverse blank dams, interaction zone of floodplain and channel flow, turbulent mixing zone, region of flow spreading, traction forces, velocity in channel, velocity at floodplain, length of region of flow spreading.
The role of floodplains for national economy has grown significantly in recent years. First of all, it is determined by their agricultural use and also by urban development in floodplains. Floodplains can give high yields due to their close location to riverbanks. Exploitation of flood-plains is often carried out by using transverse solid dams as protection, and these dams are built of the same soil from the floodplain.
Designing transverse dams in rivers with floodplain has its special features as complex morphology, kinematic and dynamic interaction of riverbank and floodplain flows [1]. The work[2] discusses design issues for transverse dams in rivers with single-side floodplain and the influence ofpartial land use between dams [3] under one sided obstruction.
The given work discusses design issues for transverse dams, symmetrically obstructing flow. The task differs from the previous works by the presence of bilateral floodplain, two zones of inter-
action between riverbank and floodplain flows, various roughness measures at the right and left floodplains, differing from those in riverbank.
The experiments have been held in schematic riverbanks with bilateral symmetrical floodplains. The experiments showed that when the flow fills the whole floodplain, the riverbank roughness, the roughness of the left and the right floodplain differ from each other.
The research result analyses show that there is significant deformation in flow depth and velocity regime, also formation of backwater takes place in head race, flow compression and spreading and natural flow restoration areas in the tailrace (pic.1.).
The velocities increase both in main riverbank and in floodplain area of flow. Flow spreading and restoration of natural flow restoration area form after compressed section.
